1. Field of the Invention
The present invention relates to an alphabet input device of a mobile communication terminal and a method thereof, and more particularly to an alphabet input device of a mobile communication terminal and a method thereof, which make it possible to input alphabets more quickly by arranging the alphabets according to the frequency of use of the alphabets and the interrelationship of the successive input and which can have a keypad arrangement optimized to a singlehanded use by smoothing fast input of the alphabets assigned to the same button and by facilitating the shift of a word/character between a capital letter and a small letter, when trying to perform the input of the alphabets in the mobile communication terminal, such as a mobile phone, a PDA and etc.
2. Description of the Related Art
In general, alphabets for inputting character in English amount to 26 in total and words made by combining the alphabets amount to about 230,000. Accordingly, in order to input the alphabets in the mobile communication terminal using a 3×4 keypad, 26 alphabets are assigned, in the plural form, to the 12 keys.
Currently, the frequency of alphabet input in the mobile communication terminal increases along with the spread of the mobile phone, the PDA and a short message service, and thus, the alphabet input device and the method thereof have been disclosed, which allow the user to be accustomed to the alphabet input in an easier way and which minimize the number of button input manipulations.
FIG. 1 is a view of a keypad for inputting alphabet according to a conventional mobile communication terminal.
As shown in FIG. 1, the keypad for inputting alphabet according to the conventional mobile communication terminal is such that a plurality of the alphabet characters are assigned to 12 keys in the order of the alphabet itself, and thus the user may have such an advantage as to easily locate a place of the alphabet character. However, the frequency of use is not taken into account at all, and thus the conventional keypad has an unreasonable arrangement in that the larger amount of pressing is required for inputting the alphabet character with the higher frequency of use.
In other words, it is required to press the input button twice or three times so as to input the alphabets with the higher frequency of use, such as ‘E’, ‘I’, ‘N’, ‘O’ and ‘S’, whereas it is required to press the input button once or twice so as to input the alphabets with the lower frequency of use, such as ‘J’, ‘Q’ and ‘X’. Accordingly, the character arrangement is inefficient in use.
Moreover, the relationship between alphabets requiring successive input is not taken into account at all. Thus, the manipulation of each input button increases when inputting the alphabets, such as ‘TH’, ‘HE’, ‘IN’ and ‘ER’, which are the succession of the alphabets with the higher frequency of use. Accordingly, it is difficult to quickly and successively input the alphabets.
In addition, when it is required to successively input the characters assigned to the same button, for example, when inputting ‘AA’, ‘AB’ or ‘AC’ using the button assigned with ‘ABC’, the user should, after inputting a first alphabet, await for a certain period of time (or an intermediate time) during which the cursor moves to a next character-place so as to input a second alphabet; otherwise, the user should manipulate a directional key to move the cursor to the next place so as to input the second alphabet. Therefore, it is impossible to perform the fast and successive input operation because of the increase in the moving distance of the finger and the slower input speed.
On the other hand, in case of the mobile communication terminal mainly used in the English-speaking countries, a function of shifting the alphabet between a capital letter and a small letter should be included in the button.
However, under the circumstance in which the shift function button should be pressed while inputting the alphabet, the user may fail to press the shift button before pressing the alphabet, because he/she pays too much attention to the spelling. In such a case, the conventional mobile communication terminal causes the inconvenience, because the cursor should be moved to a corresponding place so as to delete a corresponding alphabet by manipulating the directional key and then the corresponding alphabet should be inputted once again after pressing the shift function button.
Also, the user normally uses the above-described keypad of the mobile communication terminal with one hand. Accordingly, it is needed to enable the user to conveniently perform the alphabet input with one hand by arranging the alphabet input button and the function button in order to comply with the hand that the user mainly uses.